Property Type: Institutional
Neighborhood: Downtown  |  County: Ada  |  Building Status: Public  |  Year Built: 1871  |  Architectural Style: Italianate
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The Federal Assay Office, built in Boise, Idaho in 1871 was one of only seven offices in the country. The architect, Alfred B. Mullet was commissioned by the U.S. Congress to design the building. The style has been called “Italian Villa,” “French Chateau,” and/or “Provincial.”

Mullet constructed the office on a large parcel of land donated by a Boisean, Alexander Rossi, for the project. An assay office is the location miners would bring their gold to in order to have it separated from the invaluable rock. It would also be “assayed” for value, and stamped with a hallmark.

Naturally, the building contained heavy equipment for such purposes. The floor plan while in operation consisted of main operations downstairs, living quarters for the Chief Assayer and his family on the top floor, and rooms for the help, guards, and geothermal in the basement. The outside of the building demonstrates the main function of the building: security. Because over one and a half million dollars were deposited a year, the windows were barred, and the walls were built of local sandstone two feet thick! After the gold rush died down in the Idaho territory, the office was closed in 1933. The government then donated it to the Forest Service, which used the building as offices, and the grounds as a city park.

Evidence of this park still remains, as the small building located directly behind the offices still resembles the public restrooms it once held. During this time the Forrest Service also proposed a renovation which would have added wings to the building, diminishing the historical value. The building is now inhabited by SHPO, the State Historic Preservation Office after being turned over in 1972. The old Assay Office is significant to Idaho history because its exterior is so well preserved. It is also indicative of the impact mining had on the life of Idahoans in the late nineteenth and early twentieth centuries. This has lead to the building being recognized as a national landmark! Idaho has 10 national landmarks, only 3 of which are buildings.

Additionally, modern inhabitants say that the history has been commemorated in another way as well, in the form of miner ghost. A cleaning lady reported seeing the miner clad in a plaid shirt and boots late at night several years ago, and SHPO workers who stay late often hear the mysterious sound of mining boots in the building.